Questions

Tether is a rope, chain, or the like, by which an animal is fastened to a fixed object so as to limit its range of movement.

Cord is rope like to tie. Hence, cord is most similar in meaning to tether.

The more interesting’ needs to be replaced with ‘the most interesting’. This is because, when making comparison between two or more things, the superlative degree is used and not the comparative degree Thus, the correct formation would be, ‘This book is the most interesting of the three’.

The branch of biology that studies the different structures and functions of the cell is called Cell Biology or Cytology.

 
Cell biology (formerly called Cytology), is a Greek word: kytos, "vessel" is a branch of biology that studies the different structures and functions of the cell and focuses mainly on the idea of the cell as the basic unit of life.

The cell (from Latin cella, meaning "small room") is the basic

• Structural,

• Functional (and) 

• Biological unit of all known living organisms. 

A cell is the smallest unit of life that can replicate independently, and cells are often called the "building blocks of life". 

The IUPAC nomenclature in organic chemistry is a systematic method that is used to name organic chemical compounds as recommended by the International Union of Pure and Applied Chemistry (IUPAC).

The IUPAC name of the given complex [Co (NH₃)₄Cl₂ ]Cl is - Tetra-ammine dichloro cobalt (III) chloride.

The complex [Co (NH₃)₄ Cl₂ ] Cl ionizes an aqueous solution to furnish the chloride ion Cl⁻ and [Co (NH₃)₄ Cl₂ ] ⁺.